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81.
A. Glover A. Hilgers L. Rosenqvist S. Bourdarie 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,42(9):1564-1568
Solar particle events leading to important increase of particle fluxes at energies of order of magnitude ranging from MeV to GeV constitute an important hazard for space missions. They may lead to effects seen in microelectronics or damage to solar cells and constitute a potential hazard for manned missions. Cumulative damage is commonly expressed as a function of fluence which is defined as the integral of the flux over time. A priori deterministic estimates of the expected fluence cannot be made because over the time scale of a space mission, the fluence can be dominated by the contribution of a few rare and unpredictable high intensity events. Therefore, statistical approaches are required in order to estimate fluences likely to be encountered by a space mission in advance. This paper extends work done by Rosenqvist et al. [Rosenqvist, L., Hilgers, A., Evans, H., Daly, E., Hapgood, M., Stamper, R., Zwickl, R., Bourdarie, S., Boscher, D. Toolkit for updating interplanetary proton-cumulated fluence models. J. Spacecraft Rockets, 42(6), 1077–1090, 2005] to describe an updated predictive engineering model for the proton interplanetary fluence with energies >30 MeV. This model is derived from a complete list of solar proton fluences based on data from a number of calibrated sources covering almost three solar cycles. 相似文献
82.
Kyle Copeland Herbert H. Sauer Frances E. Duke Wallace Friedberg 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
From 1 January 1986 through 1 January 2008, GOES satellites recorded 170 solar proton events. For 169 of these events, we estimated effective and equivalent dose rates and doses of galactic cosmic radiation (GCR) and solar cosmic radiation (SCR), received by aircraft occupants on simulated high-latitude flights. Dose rate and dose estimates that follow are for altitudes 30, 40, 50, and 60 kft, in that order. 相似文献
83.
H. Nevanlinna 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Hourly magnetic readings of H and D from six geomagnetic observatories in Finland and Russia were utilized for analysis of the time behavior of the extreme space weather event of August/September 1859. The observatories cover about 200° in longitude and magnetic latitudes 45–60°N. 相似文献
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本文以某型航电任务系统研发为背景,介绍了几种经典体系结构风格的设计特点和应用。理论和研发实践相结合,项目的顺利推进证明了软件体系结构风格的分析对明确设计思路和指导代码开发具有重要意义,加快了软件研发的进度,保证软件质量,同时又增加了系统的可扩展性,降低研发成本。 相似文献
87.
Linfeng Huang Jinsong Wang Yong Jiang Zhou Chen Kai Zhao 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
Ionospheric scintillation variations are studied using GPS measurements at the low latitude station of Shenzhen (22.59°N, 113.97°E), situated under the northern crest of the equatorial anomaly region, from the Chinese Meridian Project. The results are presented for data collected during the current phase of rising solar activity (low to high solar activity) from December 2010 to April 2014. The results show that GPS scintillation events were largely a nighttime phenomenon during the whole observation period. Scintillation events mainly occurred along the inner edge of the northern crest of the equatorial anomaly in China. The occurrence of scintillations in different sectors of the sky was also investigated, and the results revealed that it is more likely for the scintillations to be observed in the west sector of the sky above Shenzhen. During the present period of study, a total number of 512 total electron content (TEC) depletions and 460 lock loss events were observed. In addition, both of these events are likely to increase during periods of high solar activity, especially because the strong scintillations are often simultaneously accompanied by TEC depletions and lock losses by GPS receivers. 相似文献
88.
基于状态时间的概念,在Ramadge-Wonham模型的基础上提出了一种新的实时离散事件系统模型。在控制目标是保持某给定谓词在闭环系统状态轨迹上为真的情况下,给出了实时控制不变性的定义。研究表明,对这类系统,存在一个状态反馈控制器使给定谓词在闭环系统状态轨迹上保持为真的充要条件是该谓词是实时控制不变的。证明了给定谓词所含的最大实时控制不变子谓词的存在性并给出了计算方法。最后,给出一个例子来说明有关结果。 相似文献
89.
Mandy J. Maguire Jonathan Brumberg Michelle Ennis Thomas F. Shipley 《Spatial Cognition & Computation》2013,13(3):254-279
Abstract Events, like objects, can be decomposed into parts. Path, the spatiotemporal trajectory of an object during an event, is the most commonly labeled event feature across the world's languages, provides important social information, and is increasingly central to theories of general event segmentation. However, little is understood about how adults visually segment paths. We apply theories developed for object segmentation to help understand path segmentation. Overall subjects segmented equivalent object shapes and event paths in similar ways following patterns predicted by Singh and Hoffman's (2001) geometric analysis of object parts. There were two notable differences between object and event segmentation: (1) event parsing occurred at points of negative curvature minima and positive curvature maxima as opposed to simply negative curvature minima; and (2) event parsing was more frequent and variable than object parsing. Implications of these results for event perception and categorization are discussed. 相似文献
90.
针对空间目标态势威胁响应和预警研究不完善的问题,为实现空间目标行为和事件的智能推理、实时响应和主动预警,保障航天活动和空间利益,提出面向行为与事件的空间目标态势本体模型(BEO-SO2)。基于基本形式本体(BFO),构建空间目标态势行为与事件本体模型。在统一时空框架下建立空间目标关系模型,实现空间目标行为执行和事件发生过程的动态推演。以空间目标碰撞威胁为背景,设计对象实体等级体系和碰撞威胁行为与事件要素,建立碰撞威胁推理规则,基于空间目标态势行为与事件本体进行实现、验证与展示。结果表明,空间目标态势行为与事件本体能够实现空间目标碰撞威胁的等级推理与预警,并指导进一步的空间活动,为航天任务与空间活动提供有效保障。 相似文献